In December 1997, North Carolina became the second state to enact a comprehensive Graduated Driver Licensing (GDL) system. The purpose of GDL is to reduce young driver crashes by introducing beginning drivers to the full range of driving experience in stages, thereby allowing them to obtain needed experience and develop maturity. This report describes changes in young driver motor vehicle crashes following enactment of the GDL program. We examined information about crashes involving drivers of passenger vehicles which was obtained from the North Carolina Crash Data File for 1997 and 1999. By 1999, nearly all 16 year-old drivers in North Carolina had begun their driving experience under the GDL program as opposed to the previous system. During 1999, 16 year-old drivers in North Carolina had 26% fewer crashes than in 1997. There was a similar pattern in injuries and fatalities among 16 year-old drivers, which declined 29% from 1997 to 1999. To address the possibility that this decline was due to a general decline in crashes throughout North Carolina, these results were compared with those for older drivers. These older drivers would reflect any general patterns, but would not have been affected by the GDL program. Whereas crashes declined by 26% among 16 year-old drivers, there was a 4% increase among drivers age 20 and older, clearly indicating that the decline among young drivers was not due to a general trend. Crashes among 17 year-old drivers declined by 6%. This probably reflects the early effects of GDL in this age group, although many 17 year-old drivers during 1999 were licensed before the GDL program took effect. The driving age population of North Carolina has been growing in recent years and this alone will result in more crashes. To adjust for population increases between 1997 and 1999, age-specific crash rates per 10,000 persons were calculated. With these adjustments for population growth, 16 year-old driver crashes were down even more (29%). Crash rates among 17 year-old drivers declined 9% and the rate for drivers 20 and older increased by one percent. A central feature of the North Carolina GDL program is a restriction on unsupervised night-time driving by novice drivers who have reached the second level of licensure. Crash data indicate that this restriction has produced the expected benefit. Whereas 16 year-old driver crashes declined by 22% during daytime hours (5 a.m. to 9 p.m.), the decrease was 47% during the restricted hours (9 p.m. to 5 a.m.). This benefit was realised despite the fact that during 1999, many 16 year-old drivers would have progressed to a Level 3 license, which does not restrict night-time driving. A large number of young North Carolina drivers are still making their way through the initial licensing levels. Consequently, it is not yet possible to estimate the enduring effect of graduated licensing in North Carolina. It is important to recognise that the initial effects will not persist at the same magnitude over time. Although these initial effects will likely decline to some extent, there is good reason to expect that a permanent decrease in young driver crashes will result from the GDL system, since these early findings indicate that GDL is working as was envisioned when it was enacted. In sum, preliminary analyses indicate that the North Carolina GDL program is having the anticipated effect on young driver crashes. Future analyses will examine effects on 17 year-old drivers, will determine which elements of the GDL program produce the greatest benefit and will look at the enduring effects of GDL on older drivers who began their driving experience under the GDL system. (A)
Abstract